KR20190068598A - Battery with low output voltage - Google Patents

Abstract

The present invention relates to an electrochemical battery cell comprising an anode, a cathode, and an ion-conducting electrolyte having a primary anode active material, the cell having an initial output selected from the range of 0.3 volts to 0.8 volts when the cell is measured at 10% (Vi-Vf) / Vi) is less than or equal to +/- 10%, and the cost between Vi and Vf is less than or equal to < RTI ID = 0.0 & (Na), potassium (K), magnesium (Mg), aluminum (Al), aluminum (Al), or the like, based on the weight or volume of the cathode active material, of 100 mAh / g or 200 mAh / ), Zinc (Zn), titanium (Ti), manganese (Mn), iron (Fe), vanadium (V), cobalt (Co), nickel (Ni), mixtures thereof, To a selected, electrochemical battery cell.

Description

Battery with low output voltage

Cross-references to Related Applications

This application claims priority from U.S. Patent Application No. 15 / 297,877, filed October 19, 2016, which is incorporated herein by reference.

Field of invention

The present invention relates generally to a battery that naturally supplies an output voltage of 0.3 volts to 0.8 volts to an external circuit without using an electrochemical battery field, and more particularly a voltage regulator (e.g., a voltage reducer or a transformer) .

The emergence of "Internet-of-Things" and next-generation sensor technology for health monitoring and artificial intelligence applications requires no recharging, and in particular, maintenance of wireless devices, wearable devices or implantable devices without replacing batteries The availability of batteries that last for decades.

As an example, it has been found that, in the case of using a sensor, an ultra-low-power monitoring sensor requires a low-voltage power source capable of operating from 0.3 V to 0.8 V without using a voltage reducer. Low operating voltage means low power consumption. The use of a voltage reducer (for example a transformer) would mean an additional power loss, which should be avoided. However, commercially available battery systems such as lithium-ion (3.7 V), lead acid (2 V), zinc-carbon / alkaline (1.5 V), zinc-air (1.4 V), and nickel- Are all voltage-mismatched, which requires a voltage reduction circuit to bring the operating voltage below 0.8 volts. In addition, most of these batteries have a low energy density in functioning throughout the life of the battery. Additionally, because the size of the remote wireless sensor is very small in most cases, the volumetric energy density of the battery is particularly important for sensor devices.

Accordingly, there is an urgent need for a long lasting primary battery that operates in the voltage range of 0.3 volts to 0.8 volts and supplies power to the wireless device, the wearable device, or the implant device without using the voltage reducer circuit. Preferably, such a battery system should also allow flexibility in adjusting the output voltage for various device power design needs.

An electrochemical battery cell is reported herein that meets the requirements described above. The battery cell

(A) an anode having a primary anode active material,

(B) a cathode having a main cathode active material, and

(C) an ion-conducting electrolyte in ionic contact with the anode and the cathode,

Where the cell has an initial output voltage Vi of a lower limit of 0.3 volts to an upper limit of 0.8 volts when measured at a 10% depth of discharge (DoD), and an initial output voltage Vi of 90% (Vi-Vf) / Vi) is less than or equal to 10% (preferably, less than or equal to 5%), and a specific capacity between Vi and Vf is less than or equal to the cathode active material weight or volume The anode is made of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), aluminum (Al), zinc Zn, Ti, Mn, Fe, V, Co, Ni, mixtures thereof, alloys thereof, or combinations thereof. Preferred anode active materials are Li, Na, Mg, Al alloys or mixtures thereof.

Discharge depth (DoD) is a well known term in the battery art. Briefly, DoD is the ratio of the actual discharge amount (in terms of specific capacity, mAh / g or mAh / cm3) to the maximum discharge amount that can be provided by the battery cell in relation to the cell weight, the anode active material weight, or the cathode active material weight to be. For example, for Li (as an anode active material, having a sufficient amount to match M), metal M (as a cathode active material) can store up to 1000 mAh of Li per M 1 gram, It is possible to discharge to 900 mAh / g, and this non-capacity of 900 mAh / g corresponds to 900 / 1,000 = 90% DoD.

When measured at a 10% discharge depth (DoD), the battery cell must deliver an initial output voltage (Vi) of 0.3 volts to 0.8 volts, preferably 0.3 volts to 0.7 volts. The battery cell also delivers a final output voltage (Vf) of less than or equal to 90% when measured at DoD and a specific capacity between Vi and Vf is preferably less than 100 mAh / g or 200 mAh / cm < 3 > Preferably, the voltage variation ((Vi-Vf) / Vi) is less than or equal to ± 10% (more preferably, less than or equal to ± 5%) from Vi to the selected Vf. The battery designer or electronics designer is free to choose Vf from 10% to 90% DoDd, but the specific capacity delivered by the battery cells Vi to Vf is preferably 100 mAh / g or 200 mAh / cm < 3 > or more.

The electrochemical battery cell may further include an anode current collector for supporting the anode and / or a cathode current collector for supporting the cathode.

The main cathode active material may be selected from a metal, a semi-metal or a nonmetal element different from the main anode active material. The metal, semimetal or nonmetal element in the cathode may be selected from the group consisting of tin (Sn), bismuth (Bi), antimony (Sb) (Al), zinc (Zn), titanium (Ti), manganese (Mn), iron (Fe), vanadium (V), cobalt (Co), nickel (Ni), selenium (Se), sulfur (S), mixtures thereof, alloys thereof, or combinations thereof. The metal, semimetal or nonmetal used as the primary cathode active material must be different from the metal used as the primary anode active material and must be capable of delivering an output voltage in the range of 0.3 volts to 0.8 volts when coupled with the primary anode active material.

The main cathode active material is also a metal oxide, a metal phosphide, or a metal sulfide, and in particular, it is a metal oxide such as tin oxide, cobalt oxide, nickel oxide, manganese oxide, vanadium oxide, iron phosphate, manganese phosphate, vanadium phosphate, Sulfide, or a combination thereof.

In certain embodiments, the primary cathode active material comprises an inorganic material selected from carbon sulfur, a sulfur compound, a lithium polysulfide, a transition metal dichalcogenide, a transition metal tricalogenconide, or a combination thereof.

The electrolyte can be selected from aqueous, organic, polymeric, ionic liquid, semi-solid, or solid state electrolytes.

Preferably, the anode additionally contains graphene as a protective material to protect the primary anode active material. More preferably, the primary anode active material is accommodated by a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam.

The graphene material for use in the anode and / or cathode may comprise an initial graphene material having less than 0.01% by weight of the non-carbon element or a non-initial graphene material having from 0.01% to 50% by weight of the non- Wherein the non-initial graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, Pin, boron-doped graphene, nitrogen-doped graphene, chemically graphene graphene, or a combination thereof.

In certain embodiments, the primary cathode active material is accommodated by a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam. Preferably, in the anode, the primary anode active material is accommodated by a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam, wherein the primary cathode active material at the cathode is accommodated by a graphene sheet , Graphene film, graphene paper, graphene mat, or graphene foam.

In the battery cell of the present invention, a graphene film, a graphene paper, a graphene mat, or a graphene foam (having the main anode active material embedded therein) at the anode is connected to the first battery terminal tab , Mat, or foam itself acts as an anode current collector) and may be a separate or additional anode current collector for supporting a graphene film, graphene paper, graphene mat, or graphene foam (e.g., , Cu foil) is not present. This feature can significantly reduce battery weight and volume.

In certain embodiments, the graphene film, graphene paper, graphene mat, or graphene foam in the cathode having the primary cathode active material embedded therein may have a battery terminal tab (graphene film, graphene paper, There is no separate or additional cathode current collector for supporting the graphene film, graphene paper, graphene mat, or graphene foam.

Most preferably, at the anode, the graphene film, graphene paper, graphene mat, or graphene foam (with the first terminal tab connected thereto) serves as an anode current collector (additional or separate Graphene film, graphene paper, graphene mat, or graphene foam (with the second battery terminal tab connected thereto) at the cathode serves as the cathode current collector, and at the cathode, There is no separate or additional cathode current collector (e.g., Al foil) to support the graphene film, graphene paper, graphene mat, or graphene foam. This feature can significantly reduce battery weight and volume.

Also, the flexibility of the graphene film, graphene paper, graphene mat, or graphene foam in both the anode and the cathode may also be used in wireless devices, wearable devices, or implantable devices that may have a particular shape Thereby enabling the production of cells.

Preferably, the specific capacity between Vi and Vf is not less than 200 mAh / g or not less than 400 mAh / cm3 (more preferably not less than 300 mAh / g or 600 mAh / cm3, and more preferably not more than 300 mAh / Preferably 400 mAh / g or 800 mAh / cm3 or more).

In certain embodiments, the cathode further comprises graphene as an electrochemical property modifier for the primary cathode active material, wherein the added graphene has a cell ratio (relative to the corresponding cell without graphene added to the cathode) Increasing the capacity, or increasing or decreasing the cell output voltage. Preferably, the primary cathode active material is bonded to the surface of the graphene or physically supported by the surface of the graphene. The graphene may contain an initial graphene material having less than 0.01% by weight of the non-carbon element, or a non-initial graphene material having from 0.01% to 50% by weight of the non-carbon element, The initial graphene may be graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, boron-doped graphene, nitrogen -Doped graphene, chemically graphene graphene, or a combination thereof.

The present invention also provides an electronic device including the electrochemical battery cell of the present invention as a power source. The electronic device may contain a sensor, a wireless device, a wearable device, or a medical device that is electronically coupled to the electrochemical battery cell of the present invention.

1a. A porous separator, a conductive filler (for example, acetylene black), and a resin binder (for example, a metal foil) may be used as the anode layer, an anode collector (e.g., Cu foil), an anode layer of a sheet of Li metal foil (Li metal is an anode active material) A conventional lithium metal battery cell (for example, a lithium _secondary battery) made of a cathode active material layer made of particles of a cathode active material (e.g., MoS ₂ or MnO ₂ ) and a cathode current collector (for example, , Primary cell).
1b. Particles of an anode active material (e.g., graphite or Si particles) mixed with an anode current collector (e.g., a Cu foil), a conductive filler (e.g. carbon black) and a resin binder (e.g., SBR) A cathode active material layer made of particles of a cathode active material (e.g., LiCoO ₂ or LiFePO ₄ ) mixed with an anode layer, a porous separator, a conductive filler and a resin binder (for example, SBR) Ion battery cell (secondary or rechargeable cell) consisting of an aluminum foil (e.g., Al foil).
2 shows a flow chart illustrating various prior art techniques for producing a peeled graphite product (flexible graphite foil and expanded graphite plate) with the process of making an initial graphene foam 40a or graphene oxide foam 40b. .
Example 3. Illustrative example showing the discharge curves (voltage versus DoD curves, or voltage vs. time at constant current density) of two hypothetical battery cells: Cell A has a total capacity of 1,500 mAh / cm3 (0 % DoD to 100% DoD), and cell B has a specific capacity of 600 mAh / cm3.
Figure 4. Possible graphene sheet-to-sheet merge mechanism.
Figure 5. Discharge curve of low-voltage Al-S cell (voltage versus DoD).
Figure 6. Discharge curve (voltage versus DoD) for low-voltage Li-P cells and graphene modified Li-P / graphene cells.
Figure 7. Discharge curve of low-voltage Li-SnO ₂ cell (voltage versus DoD).
Figure 8. Discharge curve of low-voltage Na-SnO ₂ cell (voltage versus DoD).
Figure 9. Discharge curve of the low-voltage Li-Sb cell (voltage versus DoD).
10. Discharge curve of the low-voltage Na-Sb cell (voltage versus DoD).
Figure 11. Discharge curve of low-voltage Li-Fe ₃ O ₄ cell (voltage versus DoD).
Figure 12. Discharge curve of low-voltage Na-Fe ₃ O ₄ cell (voltage versus DoD).
Figure 13. Discharge curve of low-voltage Li-Sn cell (voltage versus DoD).
Figure 14. Discharge curve (voltage versus DoD) of low-voltage Li-Mn ₃ O ₄ cells and graphene-modified cells (Li-Mn ₃ O ₄ / graphene cells).
Figure 15. Discharge curve of the low-voltage Li-Al cell (voltage versus DoD).
Figure 16. Discharge curve of low-voltage Li-MoO ₃ cell (voltage versus DoD).
Figure 17. Discharge curve of low-voltage Li-MoS ₂ cell (voltage versus DoD).

In a typical primary cell configuration, as illustrated in Fig. 1A, a cell typically comprises an anode current collector (e.g., a Cu foil), a sheet of Li metal foil as the anode layer (Li metal is an anode active material) A cathode active material layer composed of particles of a cathode active material (for example, MoS ₂ or MnO ₂ ) mixed with a porous separator, a conductive filler (for example, acetylene black) and a resin binder (for example, PVDF) (For example, Al foil). The anode active material (e.g., Li metal) may have a thin film form deposited directly on the anode current collector, such as a sheet of copper foil.

However, these lithium metal battery cells generally require a high output voltage (e.g., greater than 2.0 volts, and more, for example) because essentially all current electronics, power tools, electric vehicles, etc. operate at cell voltages higher than 1.0 volts. Typically greater than 3.0 volts). Other types of batteries, primary or secondary batteries, are also typically designed and manufactured to provide an output voltage significantly higher than 1.0 volts: for example, lithium-ion (3.7 V), lead acid (2 V) , Alkali (1.5 V), zinc-air (1.4 V), and nickel-metal hydride (1.2 V). Devices operating at voltages higher than 4.0 volts require the use of multiple cells connected in series (for example, an electric bicycle operating at 12 volts requires six serially connected lead-acid battery cells).

As illustrated in Figure IB, a lithium-ion battery cell (secondary or rechargeable cell) typically comprises an anode current collector (e.g., a Cu foil), an anode or a negative electrode, a porous separator and / A cathode electrode (typically containing a cathode active material, a conductive additive, and a resin binder), and a cathode current collector (for example, an Al foil). In a more commonly used cell configuration, the anode layer may comprise particles of an anode active material (e.g. graphite, Sn, SnO ₂ , or Si), a conductive additive (e.g., carbon black particles) For example, SBR or PVDF.

The Cu foil on the anode and the Al foil on the cathode are each attached (welded or brazed) to the terminal tabs for connection to external circuitry. However, such current collectors add weight and volume to the cell, thereby reducing the effective weight and volume energy density of the cell.

Ultra low-power monitoring sensors require the availability of low-voltage power sources operating at voltage levels ranging from 0.3 V to 0.8 V. This voltage level is preferably kept relatively constant over a long operating time. Also, most wireless devices, wearable devices, or implant devices require the size of the power source to be as small as possible. Prior art batteries, either primary or secondary batteries, do not meet these requirements.

This problem is addressed here by the present invention. One embodiment of the present invention is an electrochemical battery cell that meets the requirements described above. The battery cell comprises: (A) an anode having a primary anode active material; (B) a cathode having a primary cathode active material, and (C) an ion-conducting electrolyte in ionic contact with the anode and the cathode, wherein the cell has a lower limit of 0.3 volts when measured at a 10% An initial output voltage Vi of an upper limit value of 0.8 volts and a final output voltage Vf of 90% or less when measured in DoD, wherein the voltage fluctuation (Vi-Vf) / Vi is within ± 15% (Preferably not more than 10% and more preferably not more than 5%), and the specific capacity between Vi and Vf is not less than 100 mAh / g or not less than 200 mAh / cm3 based on the weight or volume of the cathode active material , The anode is made of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), aluminum (Al), zinc (Zn), titanium (Ti), manganese ), Vanadium (V), cobalt (Co), nickel (Ni), mixtures thereof, alloys thereof, or combinations thereof. Preferred anode active materials are Li, Na, Mg, Al and alloys thereof.

The discharge depth DoD is a ratio of the actual discharge amount (specific capacity, mAh / g or mAh / cm 3) to the maximum dischargeable amount that the battery cell can provide in terms of the cell weight, the anode active material weight, or the cathode active material weight . Figure 3 provides an illustrative example illustrating the discharge curves of two cells (voltage versus DoD curves, or voltage versus time curves at constant current density). Cell A has a total specific capacity (0% DoD to 100% DoD) of 1,500 mAh / cm3, and Cell B has a specific capacity of 600 mAh / cm3.

In the case of cell A in Fig. 3, 10% DoD occurs at 150 mAh / cm3 and 90% DoD occurs at 1,350 mAh / cm3. The most useful DoD range of 10% to 90% corresponds to a specific capacity of 1,200 mAh / cm3. At an average voltage of 0.55 volts, this range delivers an energy density of 1,200 x 0.55 = 660 Wh / cm 3 (based on the cathode volume), which is acceptable, although not exceptionally, for use in low power devices. Also, a 10% to 90% DoD, a voltage drop from 0.575 volts to 0.545 volts, a variation of (0.575-0.545) /0.575 = 5.2%.

For Cell B, 10% DoD occurs at 60 mAh / cm3 and 90% DoD occurs at 540 mAh / cm3. This range corresponds to a specific capacity of 480 mAh / cm3. However, over this range, the voltage drops from 0.50 volts to 0.33 volts, and (0.50-0.33) /0.50 = 34% variation is not allowed. Electronic devices generally require a relatively stable voltage over a useful lifetime. It is reasonable to assume that a variation of ± 10% is acceptable; Thereafter, the voltage may not fall from 0.50 volts to less than 0.45 volts over the desired range of DoD. In the case of cell B, this 0.45 volts corresponds to 35% DoD. As a result, the useful voltage range is 10% to 35% DoD, which corresponds to a useful specific capacity of (35% -10%) Х 600 = 150 mAh / cm 3, It is too low.

Thus, in summary, when measured at a 10% discharge depth (DoD), the battery cell must deliver an initial output voltage Vi of 0.3 volts to 0.8 volts, preferably 0.3 volts to 0.7 volts. The battery cell also delivers a final output voltage (Vf) of less than or equal to 90% when measured at DoD and a specific capacity between Vi and Vf is preferably less than or equal to 100 mAh / g or 200 mAh / cm < 3 > Preferably, the voltage variation ((Vi-Vf) / Vi) is less than or equal to ± 10% (more preferably, less than or equal to ± 5%) from Vi to the selected Vf. The battery designer or electronics designer is free to choose Vf from 10% to 90% DoD, but the specific capacity delivered by the battery cells Vi to Vf is preferably 200 mAh / g or 400 mAh / cm3 or higher (more preferably 300 mAh / g or 600 mAh / cm3 or higher, still more preferably 400 mAh / g or 800 mAh / cm3 or higher, even more preferably 500 mAh / More preferably at least 1,000 mAh / cm3, even more preferably at least 700 mAh / g or 1,400 mAh / cm3, and most preferably at least 1,000 mAh / g or 2,000 mAh / cm3.

The main cathode active material may be selected from a metal, a semi-metal, or a non-metallic element different from the main anode active material, and the metal, semimetal or non-metallic element in the cathode may be selected from tin (Sn), bismuth (Bi), antimony (Sb) (Al), zinc (Zn), titanium (Ti), manganese (Mn), iron (Fe), vanadium (V), copper (In), tellurium (Te), phosphorus (P) Cobalt (Co), nickel (Ni), selenium (Se), sulfur (S), mixtures thereof, alloys thereof, or combinations thereof. The metal, semimetal or nonmetal used as the primary cathode active material must be different from the metal used as the primary anode active material and must deliver an output voltage in the range of 0.3 volts to 0.8 volts when coupled with the primary anode active material.

The primary cathode active material may also be selected from metal oxides, metal phosphates, or metal sulfides, and in particular, it may be selected from tin oxide, cobalt oxide, nickel oxide, manganese oxide, vanadium oxide, iron phosphate, manganese phosphate, Cargo, transition metal sulfides, or combinations thereof.

In certain embodiments, the primary cathode active material comprises an inorganic material selected from carbon sulfur, a sulfur compound, a lithium polysulfide, a transition metal dicalcogenide, a transition metal tricalcium cyanide, or a combination thereof.

The electrochemical battery cell may further include an anode current collector for supporting the anode and / or a cathode current collector for supporting the cathode.

Preferably, the anode and / or the cathode further contain graphene as a protective material for protecting the primary anode / cathode active material. More preferably, the primary anode active material and / or the cathode active material is accommodated by a graphene sheet or embedded in a graphene film, a graphene paper, a graphene mat, or a graphene foam.

The graphene material for use in the anode and / or cathode may be an initial graphene material having less than 0.01 weight percent non-carbon element, or a non-initial graphene material having from 0.01 weight percent to 50 weight percent non- Wherein the non-initial graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, Graphene, boron-doped graphene, nitrogen-doped graphene, chemically graphene graphene, or a combination thereof.

In the battery cell of the present invention, a graphene film, a graphene paper, a graphene mat, or a graphene foam (with the main anode active material embedded therein) at the anode is connected to the first battery terminal tab A separate or additional anode current collector for supporting the graphene film, graphene paper, graphene mat, or graphene foam (e.g., a film, paper, mat, or foam itself acts as an anode current collector) , Cu foil) is not present. This feature can significantly reduce battery weight and volume, thus significantly reducing weight and volume energy density.

In certain embodiments, a graphene film, a graphene paper, a graphene mat, or a graphene foam is connected to the battery terminal tab (such as a graphene film, a graphene paper, a graphen mat, etc.) in the cathode having the primary cathode active material embedded therein , Or the graphene foam itself acts as the cathode current collector), a separate or additional cathode current collector for supporting the graphene film, graphene paper, graphene mat, or graphene foam.

Most preferably, both the anode side and the cathode side have no separate (additional) current collectors. In detail, at the anode, a graphene film, a graphene paper, a graphene mat, or a graphene foam (having a first terminal tab connected thereto) is coated with an anode current collector (additional or separate anode current collector, Graphene paper, graphene mat, or graphene foam (with the second battery terminal tab connected thereto) serves as the cathode current collector, and at the cathode, There is no separate or additional cathode current collector (e.g., Al foil) to support the graphene film, graphene paper, graphene mat, or graphene foam. This feature can significantly reduce the weight and volume of the battery and thus significantly increase the weight and volume energy density.

Also, the flexibility of the graphene film, graphene paper, graphene mat, or graphene foam in both the anode and the cathode, and the lack of Cu foil and Al foil current collectors, can also be used in wireless devices, Wearable device, or implantable device for use in portable devices. These unexpected features are highly desirable for wireless, wearable, or implantable devices.

Another unexpected feature of the present invention is the concept that graphene can modify the electrochemical properties of the anode active material or cathode active material (e. G., Change the discharge curve). Thus, in certain embodiments, the cathode further comprises a graphene as an electrochemical property modifier in the primary cathode active material, wherein the added graphene increases the cell specific capacity, increases the cell output voltage (For the corresponding cell where no graphene is added to the cathode). Preferably, the primary cathode active material is bonded to, or physically supported by, the surface of the graphene. Again, as an electrochemical modifier, graphene may contain an initial graphene material having less than 0.01% by weight of the non-carbon element, or a non-initial graphene material having from 0.01% to 50% by weight of the non-carbon element Wherein the non-initial graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, boron Doped graphene, nitrogen-doped graphene, chemically graphene graphene, or a combination thereof.

Bulk natural graphite is a 3-D graphite material having respective graphite particles composed of a plurality of crystal grains (crystal grains are graphite single crystals or crystallites) having crystal grain boundaries (amorphous or defective regions) for separating neighboring graphite single crystals. Each grain consists of a plurality of graphene planes oriented parallel to one another. The graphene plane in the graphite crystallizer consists of carbon atoms occupying a two-dimensional hexagonal lattice. In the crystal grains or monocrystals provided, the graphene planes are laminated and bonded via van der Waals forces in the crystallographic c -direction (perpendicular to the graphene plane or the base plane). Although all of the graphene planes in one grain are parallel to each other, the graphene planes at one grain and the graphene planes at adjacent grains are typically tilted in different orientations. In other words, the orientation of the various grains in graphite grains is typically different between one grains and the other grains.

The constituent graphene planes of graphite crystallites in natural or artificial graphite particles can be stripped, extracted or isolated to obtain individual graphene sheets of carbon atoms, provided that the planar van der Waals forces can be overcome. Isolated, individual graphene sheets of carbon atoms are commonly referred to as single layer graphenes. A stack of multiple graphene planes bonded through van der Waals forces in the thickness direction with a graphene interspacing of approximately 0.3354 nm is commonly referred to as multilayer graphene. The multilayer graphene plate has a graphene plane of less than 300 layers (thickness less than 100 nm), more typically less than 30 graphene planes (thickness less than 10 nm), more typically less than 20 Of the graphene plane (thickness less than 7 nm), and most typically less than 10 graphene planes (commonly referred to as several layers in the scientific community). Single layer graphenes and multilayer graphene sheets are collectively referred to as "nanographene platelets " (NGP). Graphene or graphene oxide sheets / plates (collectively, NGP) are a new class of carbon nanomaterials (2-D nanocarbons) distinct from 0-D fullerenes, 1-D CNTs, and 3-D graphites.

The inventor's research group pioneered the development of graphene materials and related production processes in early 2002 [(1) BZ Jang and WC Huang, "Nano-scaled Graphene Plates," US Patent No. 7,071,258, 2006), filed on October 21, 2002; (2) B. Z. Jang, et al. "Process for Producing nanoscaled Graphene Plates," U.S. Patent Application No. 10 / 858,814 (06/03/2004); And (3) B. Z. Jang, A. Zhamu, and J. Guo, "Process for Producing Nanoscaled Platelets and Nanocomposites," U.S. Patent Application 11 / 509,424 (08/25/2006).

In the process of the present inventors, the graphene material may contain a strong acid and / or an oxidizing agent to the natural graphite particles to obtain a graphite intercalation compound (GIC) or a graphite oxide (GO), as illustrated in FIG. 2 Intercalation. The presence of chemical species or functional groups in the interplanar space between the graphene planes serves to increase the intergranular spacing (d _{002 as} measured by X-ray diffraction), so that graphene planes along the c- Significantly reducing the van der Waals forces that otherwise would be maintained. GIC or GO is most often produced by impregnating natural graphite powder (20 in Figure 2) in a mixture of sulfuric acid, nitric acid (oxidizing agent), and other oxidizing agents (e.g., potassium permanganate or sodium perchlorate). The resulting GIC 22 is actually some type of graphite oxide (GO) particles in the presence of an oxidant during the intercalation procedure. Such a GIC or GO is subsequently washed and rinsed in water repeatedly to remove excess acid to form a graphite oxide suspension or dispersion which contains separate and visually distinct graphite oxide particles dispersed in water do. To produce graphene materials, this cleaning step, which is briefly described below, can lead to one of two treatment paths:

Path 1 involves removing water from the suspension to obtain "expandable graphite, " which is essentially a mass of dried GIC or dried graphite oxide particles. Upon exposure of the expandable graphite to a temperature typically in the range of 800 ° C to 1,050 ° C for approximately 30 seconds to 2 minutes, the GIC is subjected to a rapid 30 to 300-fold volume to form a "graphite worm" Which is a set of nearly discrete graphite flakes, each of which is peeled off but remains in an interconnected state.

In route 1A, such graphite worms (peeled graphite or "network of interconnected / non-separated graphite flakes") is a flexible graphite sheet typically having a thickness in the range of 0.1 mm (100 μm) to 0.5 mm Expanded graphite flakes "(which, by definition, are not nanomaterials) containing graphite flakes or plates that are thicker than about 100 nm, can be re-compressed to obtain a foil 26. Alternatively, It is possible to choose to use a low-strength air-mill or shear machine to simply break the graphite worms for the purpose of producing them.

In path 1B, the exfoliated graphite may be used to form separate monolayer and multilayer graphene sheets (collectively referred to as NGP 33), as disclosed in our U.S. Provisional Application No. 10 / 858,814, High strength mechanical shear (e.g., using an ultrasonic processor, high shear mixer, high intensity air jet mill, or high energy ball mill). Single layer graphene may be as thin as 0.34 nm, and multilayer graphene may have a thickness of less than 100 nm, but more typically may have a thickness of less than 10 nm (typically several layers of graphene being). A number of graphene sheets or sheets can be made of sheets 34 of NGP paper using a papermaking process.

Path 2 involves sonicating the graphite oxide suspension for the purpose of separating / isolating individual graphene oxide sheets from the graphite oxide particles. This is based on the concept that graphene flat separation is increased from 0.6 nm to 1.1 nm in highly oxidized graphite oxide at 0.3354 nm in natural graphite, which significantly weakens the van der Waals forces that keep adjacent planes together. The ultrasonic power may be sufficient to further separate the graphene flat sheet to form a separate, isolated, or separate graphene oxide (GO) sheet. Such a graphene oxide sheet is then subjected to a heat treatment at a temperature of from about < RTI ID = 0.0 > 001 < / RTI > to 10 weight percent, more typically from 0.01 weight percent to 5 weight percent, most typically and preferably, Can be chemically or thermally reduced to obtain a graphene oxide "(RGO).

For purposes of defining the claims of the present application, NGP or graphene materials may comprise a single layer and multiple layers (typically less than 10 layers) of initial graphene, graphene oxide, reduced graphene oxide (RGO) , Graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, chemically graphene graphene, doped graphene (e.g., B or N Lt; / RTI > doped). The initial graphene has essentially 0% oxygen. RGO typically has an oxygen content of from 0.001% to 5% by weight. The graphene oxide (including RGO) can have from 0.001% to 50% by weight of oxygen. All graphene materials except for the initial graphene have 0.001 wt% to 50 wt% non-carbon elements (e.g., O, H, N, B, F, Cl, Br, I, etc.). Such materials are referred to herein as non-initial graphene materials.

All types of graphene sheets (with particles of the anode active material or cathode active material) can be made in paper form, for example, using vacuum-assisted filtration procedures. All types of graphene sheets (with particles of the anode active material or cathode active material) can be made into films using coating or casting procedures. Such procedures are well known in the art.

The graphene foam can be produced by using a procedure including a blowing agent. Blowing agents or foaming agents can be used to produce cells or foamed structures through a foaming process in a variety of materials that cause hardening or phase transition, such as polymers (plastics and rubbers), glass, It is a substance that can be. This is typically applied when the foamed material is in a liquid state. Previously, it was not known that foaming agents could be used to produce foamed material while in a solid state. More significantly, it has not been taught or implied in the prior art that an aggregate of graphene sheets can be converted to graphene foam through a blowing agent. Cell structures in polymer matrices are typically created for the purpose of reducing density and increasing heat resistance and sound insulation while increasing the thickness and relative stiffness of the original polymer.

Blowing agents or related blowing mechanisms that produce voids or cells (bubbles) in a matrix for producing foamed or cell material can be classified into the following groups:

(a) Physical blowing agents: for example, hydrocarbons (e.g., pentane, isopentane, cyclopentane), chlorofluorocarbons (CFC), hydrochlorofluorocarbons (HCFC), and liquid CO ₂ . The bubble / foam-forming process is an endothermic process, i. E. It requires heat to volatilize the liquid foaming agent (e. G., From a chemical exotherm due to a melting process or crosslinking).

(b) Chemical blowing agents: for example, isocyanates, azo-hydrazine, and other nitrogen-based materials (for thermoplastic and elastomeric foams), sodium bicarbonates (e.g. used in baking soda, thermoplastic foams) . Here, gaseous products and other by-products are formed by chemical reactions, which are promoted by the exothermic heat of the process and the reacting polymer. Since the foaming reaction involves forming a low molecular weight compound that acts as a foaming gas, additional pyrogenic heat is also released. The titanium hydride powder is used as a foaming agent in the production of metal foams because it decomposes to form titanium and hydrogen gases at elevated temperatures. Zirconium (II) hydride is used for the same purpose. Immediately after formation, the low molecular weight compound will never return to the original blowing agent (s), i.e., the reaction is irreversible.

(c) Mixed physical / chemical blowing agents: Used to produce, for example, flexible polyurethane (PU) foams with very low densities. Both chemical and physical foaming can be used together to balance each other with respect to the emitted / absorbed thermal energy; As a result, temperature rise is minimized. For example, a diisocyanate and water (the reaction to form a CO ₂₎ is a mattress (mattress) the so with low density (the boiling to provide a gaseous form) of the liquid CO ₂ in the production of flexible PU foam for Is used.

(d) Mechanically injected agents: The mechanically prepared foam includes a method of introducing the bubble into a liquid polymerizable matrix (e.g., a non-vulcanizable elastomer in the form of a liquid latex). This method can be used to whisk in-air or other gas or low-boiling volatile liquid to a low-viscosity grating and inject gas into an extruder barrel or die or into an injection-molded barrel or nozzle to produce a very fine bubble or gas And uniformly dispersing the gas by the shearing / mixing action of the screw to form a solution. When the melt is molded or extruded and the part is at atmospheric pressure, the gas exits the solution just prior to solidification and expands the polymer melt.

(e) Soluble and leachable agents: soluble solid fillers, for example, solid sodium chloride crystals which are mixed in a liquid urethane system and then formed into solid polymer parts, sodium chloride is added to a solid molded part in water for a while Impregnated to form small interconnected holes in the relatively high density polymer product.

(f) The inventor has discovered that all of the five mechanisms can be used to create voids in graphene material while in a solid state. Another mechanism for creating voids in graphene materials is through the generation and vaporization of volatile gases by removing such non-carbon elements in a high temperature environment. This is a unique self-foaming process that has never been taught or presented before.

In a preferred embodiment, the graphene material in the dispersion is selected from the group consisting of initial graphene, graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, Graphene, chemically functionalized graphene, or a combination thereof. The starting graphite material for producing any of the graphen materials may be selected from the group consisting of natural graphite, artificial graphite, mesophase carbon, mesophase pitch, meso carbon microbead, soft carbon, light carbon, coke, carbon fiber, Carbon nanotubes, or a combination thereof.

For example, graphene oxide (GO) can be removed from the starting graphite material (e.g., graphite oxide) in a reaction vessel at a desired temperature for a predetermined time (typically, depending on the nature of the starting material and the type of oxidant used, For example, natural graphite powder) in an oxidizing liquid medium (for example, a mixture of sulfuric acid, nitric acid, and potassium permanganate). The resulting graphite oxide particles can then be treated with thermal stripping or ultrasonic-induced stripping to produce a GO sheet.

The initial graphene can be produced by direct ultrasonic waves of graphite particles (also known as liquid phase production) or supercritical fluid separation. Such processes are well known in the art. Many initial graphene sheets can be dispersed in water and other liquid media with the aid of a surfactant to form a suspension. The chemical blowing agent may then be dispersed in the dispersion (38 in FIG. 2). This suspension is then cast or coated on the surface of a solid substrate (e.g., a glass sheet or Al foil). Upon heating to the desired temperature, the chemical blowing agent is activated or decomposed to generate volatile gases (e.g., N ₂ or CO ₂ ), which acts to form bubbles or voids in other agglomerates of the solid graphene sheet To form an initial graphene foam 40a.

Fluorinated graphene or graphene fluoride is used herein as an example of a group of halogenated graphene materials. There are two different methods carried out to produce fluorinated graphene: (1) Fluorination of pre-synthesized graphene: This method is a method of forming fluorine by grafting graphene produced by mechanical exfoliation or CVD growth with XeF ₂ With the same fluorinating agent, or F-based plasma; (2) Peeling of multi-layer graphite fluoride: both mechanical peeling and liquid phase peeling of graphite fluoride can easily be achieved [F. Karlicky et al., " Halogenated Graphenes: Rapidly Growing Family of Graphene Derivatives " ACS Nano, 2013, 7 (8), pp 6434-6464].

The interaction of F ₂ with graphite at high temperature causes covalent graphite fluoride (CF 3) _n or (C ₂ F) _n , and at low temperature, the graphite intercalation compound (GIC) C _x F (2 = x ≤ 24 ). (CF) _n , the carbon atom is sp3-hybridized, so that the fluorocarbon layer is a corrugated portion of a trans-linked cyclohexane chair. (C ₂ F) _n , only half of the C atoms are fluorinated, and all pairs of adjacent carbon sheets are joined together by a shared CC bond. Systematic studies of the fluorination reaction have shown that the F / C ratio obtained is almost dependent on the fluorination temperature, the partial pressure of fluorine in the fluorinated gas, and the physical properties of the graphite precursor, including the degree of graphitization, particle size and specific surface area. In addition to fluorine (F ₂ ), other fluorinating agents may be used, but most of the available literature sometimes involves fluorination with F ₂ gas in the presence of fluoride.

In order to separate the layered precursor material in the form of individual layers or several layers it is necessary to overcome the attractive forces between adjacent layers and further stabilize the layer. This can be achieved by covalent modification of the graphene surface by a functional group or by non-covalent modification using a particular solvent, surfactant, polymer, or donor-acceptor aromatic molecule. The process of liquid phase exfoliation involves ultrasonication of graphite fluoride in a liquid medium.

Nitriding of graphene can be performed by exposing the graphene material, for example, graphene oxide, to ammonia at high temperature (200 ° C to 400 ° C). The nitrided graphene can also be formed by hydrothermal methods at low temperatures, for example by sealing GO and ammonia in an autoclave, after which the temperature can be increased to 150 ° C to 250 ° C. Other methods of synthesizing nitrogen doped graphene include nitrogen plasma treatment on graphene, arc-discharge between graphite electrodes in the presence of ammonia, ammonia decomposition of graphene oxide under CVD conditions, and graphene oxide and Hydrothermal treatment of urea.

In the graphene foam of the anode of the present invention, the cavity wall (cell wall or solid graphene portion) contains chemically bonded and merged graphene planes. These planar aromatic molecules or graphene planes (hexagonal carbon atoms) are physically and chemically well interconnected. The lateral dimensions (length or width) of such planes can be large (e.g., greater than 20 nm to greater than 10 microns), typically greater than or equal to the maximum crystallite size (or maximum component graphene planar dimension) of the starting graphite particles It is dozens of times. The graphen sheet or planes are essentially merged and / or interconnected to form an electron-conducting path with low resistance. It is a unique and novel class of material that has not been previously identified, developed, or likely to be present.

In order to illustrate how the process of the present invention works to produce a layer of graphene foam-protected anode material or cathode material, the present inventors have described here two examples, graphene oxide (GO) and grafine fluoride (GF) is used. These should not be construed as limiting the scope of the claims. In each case, the first step involves the preparation of a graphene dispersion (e. G. GO + water or GF + organic solvent, DMF) containing a selective blowing agent. When the graphene material is an initial graphene containing no non-carbon element, a foaming agent is required.

In step (b), the GF or GO suspension containing the particles of the anode active material or the cathode active material, but also the GF or GO suspension (21 in FIG. 2), is preferably applied to the solid substrate surface PET film or glass) or a GO layer 35 on the surface. An example of such a shear procedure is casting or coating a thin film of GF or GO suspension using a coating machine. This procedure is analogous to the layer of varnish, paint, coating, or ink coated on a solid substrate. The rollers or wipers create shear stress when the film is shaped, or when there is a high relative motion between the roller / blade / wiper and the support substrate. Very unexpectedly and remarkably, such shear action causes the planar GF or GO sheet to be well aligned along the shear direction, for example. More surprisingly, such molecular alignment or preferred orientation is not destroyed when the liquid component in the GF or GO suspension is subsequently removed to form a well-packed layer of highly ordered GF or GO sheet with at least partially dried. The dried GF or GO agglomerate 37a has a high birefringence coefficient between the in-plane direction and the normal direction to the plane.

In one embodiment, such a GF or GO layer, each of which here contains Si particles, is subsequently treated with a non-carbon element (e.g., F, O, etc.) from the graphene sheet to generate volatile gas as a by- Treated by heat treatment to activate the thermally-induced reaction and / or blowing agent to be removed. These volatile gases generate voids or bubbles inside the solid graphene material and push the solid graphene sheet into the foam wall structure to form graphene oxide foam (40b in Fig. 2). In the case where no blowing agent is added, the non-carbon element in the graphene material preferably occupies at least 10 wt% (preferably, at least 20 wt%, and more preferably at least 30 wt%) of the graphene material . The first (initial) heat treatment temperature is typically higher than 80 占 폚, preferably higher than 100 占 폚, more preferably higher than 300 占 폚, still more preferably higher than 500 占 폚 and as high as 1,500 占 폚. The blowing agent is typically activated at a temperature of from 80 캜 to 300 캜, but may be higher. The foaming process (formation of voids, cells or bubbles) is typically completed within a temperature range of 80 ° C to 1,500 ° C. Surprisingly, the chemical connection or merging between the graphene planes (GO or GF planes) in an edge-to-edge and a face-to-face manner results in a relatively low annealing temperature (e.g., even as low as 150 占 폚 to 300 占 폚 ). ≪ / RTI >

The foamed graphene material may be treated with at least a further heat treatment comprising a second temperature that is significantly higher than the first heat treatment temperature.

A suitably programmed heat treatment procedure may be carried out at only a single heat treatment temperature (e.g., only a first heat treatment temperature), at least two heat treatment temperatures (a first temperature for a predetermined time, (Or maintained at this second temperature), or any other combination of heat treatment temperatures (HTT) comprising an initial treatment temperature (first temperature) and a final heat treatment temperature (HTT) (second) . The highest or final HTT in which the dried graphene layer is formed can be divided into three distinct HTT schemes:

Method 1 (80 캜 to 300 캜): In this temperature range (the thermal reduction method and, if present, the activating agent for the blowing agent), the GO or GF layer undergoes mainly a thermally induced reduction reaction, The content is typically reduced from 20% to 50% (of O in GO) or from 10% to 25% (of F in GF) to about 5% to 6%. This treatment can result in a reduction in the spacing between grains in the foam wall of approximately 0.6 nm to 1.2 nm (at dry) to approximately 0.4 nm and an increase in thermal conductivity of up to 200 W / mK per specific gravity unit and / cm. < / RTI > (Since the degree of porosity of the graphene foam material, and thus the level of specific gravity can vary, and both the thermal conductivity and the electrical conductivity vary with specific gravity when providing the same graphene material, These property values should be divided by specific gravity to facilitate a fair comparison.) Even at these low temperature ranges, some chemical linkage occurs between graphene sheets. The planar spacing between GO or GF is kept relatively large (0.4 nm or greater). There are a number of O- or F-containing functionalities.

Method 2 (300 ° C to 1,500 ° C): Important events occur in this temperature range: these events are related to the formation of a graphene foam structure. In such chemical linkages, extensive chemical combinations, polymerization, and crosslinking occur between adjacent GO or GF sheets. Oxygen or fluorine content is typically reduced to less than 1.0% (e.g., 0.7%) after chemical linkage, resulting in a reduction in graphene spacing of up to approximately 0.345 nm. This is in sharp contrast to conventional graphitizable materials (e.g., carbonized polyimide films) that typically require temperatures as high as 2,500 ° C to initiate graphite, so that some initial re- It means that it has been started. This is another distinctive feature of the graphene foam of the present invention and its production process. This chemical coupling reaction results in an increase in thermal conductivity up to 250 W / mK per specific gravity unit and / or an increase in electrical conductivity up to 2500 S / cm to 4,000 S / cm per specific gravity unit.

Method 3 (1,500 ° C to 2,500 ° C): In this sorting and re-graphitizing mode, extensive graphitization or graphene flattening occurs, which significantly improves the degree of structural alignment in the foam wall. As a result, the oxygen or fluorine content is typically reduced to 0.01% and the graphene spacing is reduced to approximately 0.337 nm (achieving a graphitization degree of 1% to about 80%, depending on the actual HTT and time length). The improved degree of alignment is also reflected by an increase in thermal conductivity up to 350 W / mK per specific gravity unit, and / or an increase in electrical conductivity up to 3,500 S / cm per specific gravity unit.

Method 4 (above 2,500 ° C): Re-graphitization or recrystallization.

The graphene foam structure of the present invention containing an anode active material or a cathode active material therein is formed by applying a dried GO or GF layer to a temperature program including at least a first method (typically, More preferably from 1 hour to 4 hours in the temperature range), more typically the first two modes (preferably from 1 hour to 2 hours), more usually the first three modes And 0.5 hours to 2.0 hours), and all four methods (including Method 4 for 0.2 hour to 1 hour, which can be performed to achieve the highest conductivity) .

Wherein the graphene material is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, chemically graphene graphene, Or a combination thereof, and when the maximum heat treatment temperature (e.g., both the first heat treatment temperature and the second heat treatment temperature) is less than 2,500 占 폚, the obtained solid graphene foam Typically contains a content of non-carbon elements of from 0.01 wt% to 2.0 wt% (non-initial graphene foam).

The X-ray diffraction pattern was obtained with an X-ray diffractometer equipped with CuKcv radiation. The shift and broadening of the diffraction peaks were corrected using silicon powder standards. The degree of graphitization (g) is calculated using the equation of Mering, d ₀₀₂ = 0.3354 g + 0.344 (1-g) (where d ₀₀₂ is the interlayer spacing of graphite or graphene crystals in nm) Line pattern. This equation is valid only when d ₀₀₂ is approximately 0.3440 nm or less. Graphene foam walls with d ₀₀₂ higher than 0.3440 nm may be coated with an oxygen- or fluorine-containing functional group that acts as a spacer (e.g., -F, -OH on the graphene molecular plane surface or edge, > O, and -COOH).

Another structural index that can be used to characterize the degree of alignment of graphene planes stacked and bonded in the foam wall of graphene and conventional graphite crystals is "mosaic spread" ) Maximum reflection width of the rocking curve of the reflection (X-ray diffraction intensity). This degree of alignment characterizes the graphite or graphene crystal size (or grain size), the grain size and the amount of other defects, and the desired degree of grain orientation. Almost complete single crystals of graphite are characterized by having a mosaic diffusion value of 0.2 to 0.4. Most of the inventive graphene walls have a mosaic diffusion value in this range of 0.2 to 0.4 (when produced at a heat treatment temperature (HTT) of 2,500 占 폚 or more). However, some of the values are in the range of 0.4 to 0.7 when HTT is 1,500 ° C to 2,500 ° C, and 0.7 to 1.0 when HTT is 300 ° C to 1,500 ° C.

Figure 4 illustrates a suitable chemical linking mechanism where only two aligned GO molecules are shown as an example, and multiple GO molecules can be chemically linked together to form a foam wall. In addition, the chemical linkage can also occur on a face-to-face basis, not just an edge-to-edge for GO, GF, and chemically functionalized graphene sheets. This linking and merging reaction proceeds in such a way that the molecules are chemically merged, linked, and integrated into one single entity. Grain sheets (GO or GF sheets) completely lose their original identity, which is no longer a separate sheet / plate / flake. The resulting product is not a simple aggregate of individual graphene sheets but a single entity that is a network of intrinsically interconnected giant molecules with essentially infinite molecular weights. It may also be described as a graphene polycrystalline (having several grains, but typically not having an identifiable and well-defined grain boundaries). All component graphene planes are very large in side dimension (length and width) and when the HTT is high enough (e.g., above 1,500 ° C or much higher), these graphene planes are essentially bonded together. The graphene foam of the anode or cathode layer of the present invention has the following unique and novel characteristics that have not been taught or implied in the prior art. This feature does not require that such an electrode layer (with the active material embedded therein) to also function as a current collector to have a separate current collector at the anode or cathode:

(1) In an in-depth study using a combination of SEM, TEM, selected region diffraction, X-ray diffraction, AFM, Raman spectroscopy and FTIR, it is stated that the graphene foam walls consist of several giant graphene planes nm, much more typically more than 100 nm, sometimes much more than 1 μm, and in many cases, much more than 10 μm, or even much more than 100 μm. These giant graphene planes are often formed along the thickness direction (crystallographic c-axis direction) through van der Waals forces (as in conventional graphite crystallizers) as well as covalent bonds when the final heat treatment temperature is lower than 2,500 ° C Laminated and bonded. In this case, although not wishing to be bound by theory, Raman and FTIR spectroscopy studies indicate coexistence of sp ² (dominant) and sp ³ (present but weak) electron configurations, rather than the usual sp ² in graphene .

(2) These interconnected large graphene surfaces in the graphene foam wall form an integrated 3D network of highly conductive and resilient graphene, which is capable of reversing the foam voids and forming anodes in the voids without significant anode electrode expansion or contraction in the battery Thereby expanding and contracting the same as the active material particles.

(3) Such graphene foam walls are not made by bonding or bonding separate flakes / plates together with resin binders, linkers, or adhesives. Instead, the GO sheet (molecule) from the GO dispersion or the GF sheet from the GF dispersion can be incorporated into the GF sheet through a covalent linkage or formation of covalent bonds, without using any externally added linker or binder molecules or polymers It is merged into a graphene entity. For a lithium battery characterized by such an anode layer, it is not required to have a non-active material, such as a resin binder or a conductive additive, which can not store lithium. This suggests a reduced amount of non-active or increased amount of active material in the anode, effectively increasing the specific capacity per total anode weight (in mAh / g, of the composite).

(4) Grainfill void walls are typically polycrystals of large graphene grains with incomplete or poorly defined grain boundaries. These entities are derived from GO or GF suspensions, which are also obtained from natural graphite or artificial graphite particles which inherently have a large number of graphite crystallites. These starting graphite crystallites have an initial length ( L _a in the crystallographic a -axis direction), an initial width ( L _b in the b -axis direction), and a thickness ( L _c in the c -axis direction) before being chemically oxidized or fluorinated, . Upon oxidation or fluorination, these initial distinct graphite particles are highly aromatic graphene oxide or graphene fluoride having a significant concentration of edge- or surface-containing functional groups (e.g., -F, -OH, -COOH, etc.) It is chemically modified into a molecule. In the suspension these aromatic GO or GF molecules lose their original identity as a part of the graphite particles or flakes. Upon removal of the liquid component from the suspension, the resulting GO or GF molecules form an essentially amorphous structure. Upon heat treatment, such GO or GF molecules are chemically incorporated and linked into a single or monolithic graphene entity that constitutes the foam wall. These foam walls are highly aligned.

The single graphene solids obtained in the foam wall typically have _a length or width considerably greater than the original crystallites L _a and L _b . The length / width of this graphene foam wall entity is considerably larger than the original crystallites L _a and L _b . Even in the polycrystalline graphene wall structure, the individual grains have _a length or width considerably greater than the original crystallites L _a and L _b .

(5) The large length and width of the graphene plane make the foam wall have high mechanical strength and elasticity. In comparative experiments, we have found that commonly produced graphene foams made of aggregates of separate graphene sheets without such features (i.e., without chemical incorporation of graphene faces) are relatively weak, fragile, non-elastic (The deformation is not reversible).

(6) the presence of such unique chemical composition (including oxygen or fluorine content), morphology, crystal structure (including intergranular spacing), and structural features (e.g., high degree of orientation, small defects, incomplete grain boundaries, Gap- or GF-induced graphene foams have a unique characteristic of good thermal conductivity, electrical conductivity, mechanical strength and stiffness (modulus of elasticity), due to the absence of a gap between the graphene sheets and virtually no interruption in the graphene plane .

The following examples are used to illustrate some specific details of the best mode for carrying out the invention and are not to be construed as limiting the scope of the invention.

Example 1: Evaluation of various battery cells

For electrochemical testing, several types of anodes and cathodes were prepared. For example, a layer-type anode or cathode was prepared by simply roll-pressing a foam (including an anode active material or a cathode active material embedded therein) against a sheet of a Cu foil (as the anode current collector). Some foam samples containing the anode active material were used as the anode electrode without using a separate Cu foil current collector. Some foam samples containing the cathode active material were used as cathode electrodes without using a separate Al foil current collector.

For comparison, a slurry coating was also used to make conventional electrodes. For example, 85 wt% of active material (SnO ₂ particles, 7 wt% of acetylene black (Super-P), and 8 wt% of polyvinylidene fluoride (NMP) dissolved in N-methyl- After the slurry was coated on the Cu foil, the electrode was dried in vacuo at 120 DEG C for 2 hours to remove the solvent before pressurization.

Thereafter, the electrode was cut into disks (? = 12 mm) and dried in vacuum at 100 占 폚 for 24 hours. Electrochemical measurements were made using a lithium metal (as an example) as a counter / reference electrode, a Celgard 2400 membrane as a separator, and a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) (3 V) coin-type cell with a 1 M LiPF ₆ electrolyte solution dissolved in a 1: 1 (v / v EC-DEC, 1: 1 v / v) Various anode material compositions and cathode material compositions were evaluated. The cell assembly was run in an argon-filled glove box. CV measurements were performed with an electrochemical workstation at a scanning rate of 1 mV / s to 100 mV / s. The electrochemical performance of various cells was also assessed by constant current charge / discharge cycling at a current density of 50 mA / g to 1,000 mA / g using a LAND electrochemical workstation. All-cell pouches were also prepared and tested.

Examples of the following low-voltage cells may be connected to a sensor, a miniature driver, a hearing aid (an example of a small medical device), a small radio circuit, a wearable device, and the like (and connected in our lab) .

Example 2: Low-voltage Al-S cell (aqueous or organic electrolyte)

From the electrochemical reaction point of view, sulfur (S) is a divalent material capable of accepting / providing two electrodes during the redox reaction. The actual capacity is approximately 1,980 mAh / cm3. When paired with an aluminum anode, the output voltage was found to be about 0.73 V (FIG. 5). The voltage variation between 10% DoD and 90% DoD is ± 2.1%.

Example 3: Low-voltage Li-P cell

M ₂ (M ₂ = P) is a trivalent material capable of accepting / providing three electrodes during the redox reaction. The actual capacity is approximately 2,371 mAh / cm3 at 100% DoD (Fig. 6). In the case of a pair with the lithium anode, this provided an output voltage of about 0.32 V. The voltage variation between 10% DoD and 90% DoD is ± 14%. When 20 wt% graphene was present in the cathode, the discharge curve was moved up to 0.1 volt total, and the slope was significantly reduced (more stable voltage output). This unexpected improvement is very beneficial.

Example 4: Low-voltage Li-SnO ₂ cell

M ₄ (compound A _y B _z = SnO ₂ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The discharge curve consists of two areas, a level plateau and a slope curve (Fig. 7). The actual capacity of the slope curve is approximately 6,157 mAh / cm3 at 100% DoD. When paired with the lithium anode and only the tilt region was used, it provided an output voltage of about 0.35 V. The voltage variation between 10% DoD and 90% DoD is ± 68%. However, since the cost amount is too large, Vf having a voltage fluctuation ((Vi-Vf) / Vi) of ± 10% or less can be confirmed.

Example 5: Low-voltage Na-SnO ₂ cell

M ₄ (compound A _y B _z = SnO ₂ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The discharge curve is composed of two regions, that is, a level plateau and a slope curve (Fig. 8). The actual capacity is approximately 3,315 mAh / cm3 at 100% DoD. When paired with the sodium anode and only the plateau region was used, it provided an output voltage of about 0.55 V. The voltage variation between 10% DoD and 90% DoD is ± 5%.

Example 6: Low-voltage Li-Sb cell

M ₇ (Sb) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,355 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.80 V (Figure 9). The voltage variation between 10% DoD and 90% DoD is ± 2.4%.

Example 7: Low-voltage Na-Sb cell

M ₇ (Sb) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,355 mAh / cm3. When paired with the sodium anode, this provided an output voltage of about 0.47 V (FIG. 10). The voltage variation between 10% DoD and 90% DoD is ± 2.4%.

Example 8: Low-voltage Li-Fe ₃ O ₄ cell

M ₈ (compound A _y B _z = Fe ₃ O ₄ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,650 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.83 V (FIG. 11). The voltage variation between 10% DoD and 90% DoD is ± 3.3%.

Example 9: Low-voltage Na-Fe ₃ O ₄ cell

M ₈ (compound A _y B _z = Fe ₃ O ₄ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,650 mAh / cm3. When paired with the sodium anode, this provided an output voltage of about 0.5 V (Figure 12). The voltage variation between 10% DoD and 90% DoD is ± 3.3%.

Example 10: Low-voltage Li-Sn cell

M ₉ (Sn) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 5,818 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.42 V (Figure 13). The voltage variation between 10% DoD and 90% DoD is ± 48%.

Example 10: Low-voltage Li-Mn ₃ O ₄ and graphene-modified Li-Mn ₃ O ₄ cells

M ₁₀ (compound A _y B _z = Mn ₃ O ₄ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,615 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.32 V (Figure 14). The voltage variation between 10% DoD and 90% DoD is +/- 6.5%. When the cathode active material (nanoparticles of Mn ₃ O ₄ ) is bonded to the nitrided graphene sheet, the cell output voltage is shifted to a more useful range, and the slope is also reduced (more plasto curves).

Example 11: Low-voltage Li-Al cell

M ₁₁ (Al) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 2,748 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.30 V (Figure 15). The voltage variation between 10% DoD and 90% DoD is ± 1.8%.

Example 12: Low-voltage Li-MoO ₃ cell

M ₁₂ (compound A _y B _z = MoO ₃ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 3,503 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.41 V (Figure 16). The voltage variation between 10% DoD and 90% DoD is ± 14%.

Example 13: Low-voltage Li-MoS ₂ cell

M ₁₃ (compound A _y B _z = MoS ₂ ) is a multivalent material capable of accepting / providing multiple electrons during the redox reaction. The actual capacity is approximately 2,509 mAh / cm3. When paired with the lithium anode, this provided an output voltage of about 0.58 V (Figure 17). The voltage variation between 10% DoD and 90% DoD is ± 6.4%.

Example 14: Preparation of distinct functionalized GO sheet and graphene foam

Cut graphite fibers and natural graphite particles having an average diameter of 12 탆 were separately used as a starting material and impregnated with a mixture of concentrated sulfuric acid, nitric acid, and potassium permanganate (as chemical intercalate and oxidizing agent) (GIC) was prepared. The starting material was first dried in a vacuum oven at 80 < 0 > C for 24 hours. A mixture of concentrated sulfuric acid, fuming nitric acid, and potassium permanganate (4: 1: 0.05 weight ratio) was then slowly added to the three-necked flask containing the fiber segments under proper cooling and stirring. After 5 to 16 hours of reaction, the acid-treated graphite fibers or natural graphite particles were filtered and thoroughly washed with deionized water until the pH level of the solution reached 5. After drying treatment at 100 DEG C overnight, the obtained graphite intercalation compound (GIC) or graphite oxide fiber was re-dispersed in water-alcohol to form a slurry.

In one sample, 5 grams of graphite oxide fibers were mixed with a 2,000 ml alcohol solution consisting of alcohol having a ratio of 15:85 and distilled water to obtain a slurry mass. Thereafter, the slurry mixture was subjected to ultrasonic irradiation with an output of 200 W for various lengths of time. After 20 minutes of sonication, the GO fibers were effectively stripped and separated into a thin graphene oxide sheet having an oxygen content of approximately 23% to 31% by weight. Adding ammonia to the resulting suspension of the first port (pot), and by this, more ultrasound for 1 h NH ₂ - to form a functionalized graphene oxide (f-GO). The GO sheet and functionalized GO sheet were separately diluted to a weight fraction of 5% and the desired amount of SnO ₂ particles (as an example of a cathode active material in a low-voltage cell) was added to the suspension. Subsequently, 2% baking soda as a blowing agent was added to the GO / SnO ₂ or f-GO / SnO ₂ suspension to form a mixture slurry. The resulting slurry was allowed to settle in the vessel for 2 days without any mechanical disturbance.

Thereafter, the obtained slurry containing GO / SnO ₂ or f-GO / SnO ₂ was comma-coated on the surface of the PET film. After removal of the liquid, the resulting coating film has a thickness of 100 [mu] m to 800 [mu] m. After the film was formed a foamed structure by treatment with a heat treatment, including the initial heat treatment temperature of 500 ℃ for 2 hours (in a mixture of H ₂ and N _2). Thereafter, the foams were exposed to different specimens (in an Ar gas atmosphere) at a second temperature of 800 ° C to 1200 ° C.

Example 15: Preparation of a single layer graphene sheet from meso carbon microbeads (MCMB) and graphene foam

Meso carbon microbeads (MCMB) were supplied by China Steel Chemical Co. (Kaohsiung, Taiwan). This material has a density of about 2.24 g / cm3 with a median particle size of about 16 microns. MCMB (10 grams) was intercalated with an acid solution (4: 1: 0.05 ratio of sulfuric acid, nitric acid, and potassium permanganate) for 48 hours to 96 hours. Upon completion of the reaction, the mixture was poured into deionized water and filtered. Intercalated MCMB was washed repeatedly in 5% HCl solution to remove most of the sulfate ions. Thereafter, the sample was repeatedly washed with deionized water until the pH of the filtrate was at least 4.5. Thereafter, the slurry was sonicated for 10 minutes to 100 minutes to produce a GO suspension. TEM and nuclear microscopy studies show that most GO sheets were single layer graphene when the oxidation treatment was over 72 hours and 2- or 3-layer graphene when the oxidation time was between 48 hours and 72 hours.

The GO sheet contains an oxygen ratio of approximately 35% to 47% by weight for an oxidation treatment time of 48 hours to 96 hours. The GO sheet was suspended in water. MoO ₃ particles (another example of a cathode active material) having a diameter of 1 탆 to 6 탆 were added to the GO suspension. Baking soda (5% to 20% by weight) as a chemical blowing agent was also added to the suspension immediately before casting. Thereafter, the suspension was cast on a glass surface using a doctor blade to apply shear stress to induce GO sheet orientation. Several samples were cast, some containing blowing agent and some not. The resulting GO film has a thickness that can vary from approximately 10 [mu] m to 500 [mu] m after removal of the liquid.

The various GO film sheets with or without blowing agent were then treated with a heat treatment comprising an initial (first) thermal reduction temperature of 80 ° C to 500 ° C for 1 to 5 hours. This first heat treatment produced a graphene foam. Thereafter, the foam was treated at a second temperature of 750 ° C to 950 ° C for 4 hours.

Example 16: Preparation of initial graphene film and foam (0% oxygen)

Recognizing the possibility of a high defect population in the GO sheet acting to reduce the conductivity of individual graphene planes, the inventors have found that the initial graphene sheets (non-oxidized and oxygen-free, non-halogenated and halogen- Etc.) could lead to graphene foam with higher thermal conductivity. Early graphene sheets were produced by direct ultrasonic treatment or liquid phase production processes.

In a typical procedure, a suspension was obtained by dispersing 5 grams of graphite flakes milled to about 20 microns or less in size in 1,000 mL of deionized water (containing 0.1 wt% of a dispersant, Zonyl® FSO from DuPont). An ultrasonic energy level of 85 W (Branson S450 ultrasonic) was used for stripping, separation, and size reduction of the graphene sheet for a period of 15 minutes to 2 hours. The resulting graphene sheet is an initial graphene that is not oxidized at all and is free of oxygen and relatively defect free. The initial graphene has essentially no non-carbon elements.

(N, N-dinitrosopentamethylenetetramine or 4,4'-oxybis (benzenesulfonylhydrazide) and MoS ₂ particles (0 to 30% by weight based on the graphene material) (As an example of a cathode active material) was added to the suspension containing the initial graphene sheet and the surfactant. The suspension was then slot-die-coated on the surface of the PET film, which resulted in a shear stress- The obtained graphen-Si film has a thickness of approximately 100 μm to 750 μm after removal of the liquid.

Thereafter, the graphene film was treated with a heat treatment comprising an initial (first) temperature of 80 ° C to 1,500 ° C for 1 hour to 5 hours, which was followed by graphene film (in the case of 0% blowing agent) or foam layer Was used. Subsequently, some of the initial foam samples were heat treated at a second temperature of 700 ° C to 2,500 ° C.

Example 17: Preparation of graphene oxide (GO) suspension from natural graphite and subsequent manufacture of GO foam

The graphite oxide was prepared by oxidizing graphite flakes having a ratio of 4: 1: 0.05 at 30 DEG C to an oxidant liquid consisting of sulfuric acid, sodium nitrate, and potassium permanganate. When the natural graphite flakes (particle size of 14 mu m) are immersed and dispersed in the oxidant mixture liquid for 48 hours, the suspension or slurry appears optically opaque and dark and remains. After 48 hours, the reaction mass was washed three times with water to adjust the pH value to at least 3.0. A series of GO-water suspensions was then prepared by adding a final amount of water. The present inventors have observed that a GO sheet forms a liquid crystal phase when the GO sheet occupies a weight fraction of more than 3%, and typically 5% to 15%.

By distributing and coating the GO suspension (containing particles of the anode active material or the cathode active material) on a polyethylene terephthalate (PET) film in a slurry coater and removing the liquid medium from the coated film, Of a thin film. Several GO film samples are then subjected to a thermal reduction treatment at a first temperature of from 100 DEG C to 500 DEG C for a time period of typically from 1 hour to 10 hours and a second step of thermal reduction treatment at a second temperature of from 750 DEG C to 1,500 DEG C for 0.5 to 5 hours Treated with different heat treatments, including a thermal reduction process, and then treated with a controlled cool-down procedure. Along with this heat treatment, and also under compressive stress, the GO film was transformed into graphene foam.

Separately, a certain amount of hydrazine as a chemical reducing agent was added to the GO suspension (containing the active material particles) to obtain a reduced GO (RGO) suspension. Thereafter, the RGO suspension was treated with a well-known vacuum-assisted filtration procedure to form RGO paper.

Example 18: Preparation of graphene foam (containing particles of an anode active material or a cathode active material) from graphene fluoride

Although several processes have been used by the present inventors to produce GF, only one process is described herein as an example. In a conventional procedure, highly peeled graphite (HEG) was prepared from the intercalated compound C ₂ F x ClF ₃ . The HEG was further fluorinated by the vapor of chlorine trifluoride to obtain fluorinated highly peeled graphite (FHEG). The precooled Teflon reactor was filled with 20 mL to 30 mL of liquid precooled ClF ₃ , the reactor was closed and cooled to liquid nitrogen temperature. Thereafter, HEG of 1 g or less was placed in a container having a hole for introducing ClF ₃ gas, and placed inside the reactor. 7 to 10 days, a gray-beige product having the formula C ₂ F was formed.

Subsequently, a small amount of FHEG (approximately 0.5 mg) was mixed with 20 mL to 30 mL of an organic solvent (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, tert-butanol, isoamyl alcohol) Treated with ultrasound (280 W) for 30 minutes to form a homogeneous yellow dispersion. The 5 minute sonication was sufficient to obtain a relatively homogeneous dispersion, but a longer sonication time ensured better stability. Thereafter, particles of the anode active material or the cathode active material were added to the dispersion. Upon casting on a glass surface while removing the solvent, the dispersion became a brown film formed on the glass surface. When the GF film was heat treated, fluorine released as a gas, which helped to create voids in the film. In some samples, a physical blowing agent (N ₂ gas) was injected into the wet GF film while casting. These samples exhibit much higher void volume or lower foam density. Without using a blowing agent, the resulting graphene fluoride foam exhibits a physical density of 0.35 g / cm3 to 1.38 g / cm3. When a foaming agent is used (foaming agent / GF weight ratio of 0.5 / 1 to 0.05 / 1), a density of 0.02 g / cm 3 to 0.35 g / cm 3 is obtained. Typical fluorine content was 0.001% (HTT = 2,500 ° C) to 4.7% (HTT = 350 ° C), depending on the final heat treatment temperature involved.

Example 19: Preparation of graphene foam (containing particles of an anode active material or a cathode active material) from nitrided graphene

The graphene oxide (GO) synthesized in Example 2 was finely divided with different proportions of urea, and the pelletized mixture was heated in a microwave reactor (900 W) for 30 seconds. The product was washed several times with deionized water and vacuum dried. In this way, the graphene oxide is simultaneously reduced and doped with nitrogen. The products obtained at the graphene: urea mass ratio of 1: 0.5, 1: 1 and 1: 2 were designated as NGO-1, NGO-2 and NGO-3, respectively, and the nitrogen content of these samples, as confirmed by elemental analysis 14.7 wt%, 18.2 wt% and 17.5 wt%, respectively. Such nitrided graphene sheets remain dispersible in water. Thereafter, particles of the anode active material or the cathode active material were added to the dispersion. The suspension obtained was then cast, dried, and initially heat treated at a temperature of from 200 캜 to 350 캜 as a first heat treatment temperature, followed by heat treatment at a second temperature of 1,500 캜. The nitrided graphene foam obtained exhibits a physical density of 0.45 g / cm3 to 1.28 g / cm3. The typical nitrogen content of the foam is 0.01% (HTT = 1,500 ° C) to 5.3% (HTT = 350 ° C), depending on the final heat treatment temperature involved.

Example 20: Characterization of various graphene foams and conventional graphite foams

The internal structure (crystal structure and orientation) of the heat-treated films on several dried GO layers and different heat treatment stages was investigated using X-ray diffraction. The X-ray diffraction curve of natural graphite typically shows a peak at approximately 2? = 26 °, which corresponds to a graphene spacing (d ₀₀₂ ) of approximately 0.3345 nm. Upon oxidation, the GO obtained shows an X-ray diffraction peak at approximately 2? = 12 °, which corresponds to a graphene spacing (d ₀₀₂ ) of approximately 0.7 nm. With respect to some heat treatments at 150 ° C, the dried GO compacts show the formation of a hump centered at 22 °, which discloses a process for reducing the intergranular spacing due to the initiation of chemical bonding and alignment processes . For a heat treatment temperature of 2,500 ° C for 1 hour, the d ₀₀₂ spacing decreased to approximately 0.336 nm, close to 0.3354 nm for graphite single crystals.

For a heat treatment temperature of 2,750 ° C for one hour, the d ₀₀₂ interval is reduced to approximately 0.3354 nm, which is the same as graphite single crystal. Also, the second diffraction peak with high intensity appears at 2? = 55 °, which corresponds to X-ray diffraction from the (004) plane. The (004) peak intensity, or the I (004) / I (002) ratio for the (002) intensity on the same diffraction curve is a good indicator of the degree of crystallization completeness of the graphene plane and the desired orientation. (004) peak is absent or relatively weak, with an I (004) / I (002) ratio of less than 0.1, for all graphite materials heat treated at a temperature of less than 2,800 ° C. I (004) / I (002) ratios for graphite materials (e.g., highly oriented pyrolytic graphite, HOPG) heat treated at 3,000 ° C to 3,250 ° C range from 0.2 to 0.5. In contrast, graphene foam produced with a final HTT of 2,750 캜 for one hour exhibited a ratio of I (004) / I (002) of 0.78 and a mosaic diffusion value of 0.21, which is practically complete with a good degree of preferred orientation Indicates graphene single crystals.

The "mosaic diffusion" value is obtained from the maximum half width of the (002) reflection in the X-ray diffraction intensity curve. This index for the degree of alignment is characterized by the amount of graphite or graphene crystal size (or grain size), grain size and other defects, and the degree of desired grain orientation. Almost complete single crystals of graphite are characterized by having a mosaic diffusion value of 0.2 to 0.4. Part of the graphene foam of the present invention has a mosaic diffusion value in this range of from 0.2 to 0.4 when produced using a final heat treatment temperature of at least 2,500 占 폚.

It is important that a heat treatment temperature as low as 500 DEG C is sufficient to allow the average graphene spacing in the GO sheet along the air gap wall to be less than 0.4 nm and to be closer to natural graphite or graphite single crystals. An advantage of this method is that such a GO suspension strategy can re-organize, re-orient, and chemically incorporate planar graphene oxide molecules from differently different graphite particles or graphene sheets into a unified structure, The plane is larger in the side dimension (essentially larger than the length and width of the graphene plane in the original graphite particle). A possible chemical linking mechanism is illustrated in Fig. This provides exceptional structural uncertainty, flexibility, high thermal conductivity and high electrical conductivity values, so that a graphene foam or film layer (containing an anode active material or a cathode active material embedded therein) can also function as a current collector Let's do it. It is not necessary to have separate (additional) anode current collectors and cathode current collectors.

Claims (24)

An electrochemical battery cell comprising an anode having a primary anode active material, a cathode having a primary cathode active material, and an ion-conducting electrolyte in ionic contact with the anode and the cathode,
The initial output voltage Vi of the lower limit of 0.3 volts to the upper limit of 0.8 volts when the cell is measured at a 10% discharge depth (DoD), and the final output voltage Vf when measured at DoD of 90% And,
The voltage fluctuation ((Vi-Vf) / Vi) is ± 10% or less,
The amount of charge between Vi and Vf is 100 mAh / g or 200 mAh / cm3 or more based on the weight or volume of the cathode active material,
Wherein the main anode active material is selected from the group consisting of lithium, sodium, potassium, magnesium, aluminum, zinc, titanium, manganese, iron, Vanadium (V), cobalt (Co), nickel (Ni), mixtures thereof, alloys thereof, or combinations thereof,
Wherein the main cathode active material is selected from metal oxides, metal phosphates, metal sulfides, or metals or semi-metals different from the main anode active material,
In the cathode, the metal or semimetal is selected from the group consisting of Sn, Bi, Sb, In, Tell, P, Mg, Al, (Zn), titanium (Ti), manganese (Mn), iron (Fe), vanadium (V), cobalt (Co), nickel (Ni), selenium ≪ / RTI > The method according to claim 1,
Wherein the anode further comprises graphene as a protective material. 3. The method of claim 2,
Wherein the primary anode active material is contained in a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam. 3. The method of claim 2,
Wherein said graphene comprises an initial graphene material having less than 0.01 weight percent non-carbon element or a non-initial graphene material having between 0.01 weight percent and 50 weight percent non-carbon element,
Wherein said non-initial graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, boron- Pin, nitrogen-doped graphene, chemically functionalized graphene, or combinations thereof. The method according to claim 1,
Wherein the primary cathode active material is contained in a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam. The method of claim 3,
Wherein the primary cathode active material is contained in a graphene sheet or embedded in a graphene film, graphene paper, graphene mat, or graphene foam. The method of claim 3,
Wherein the graphene film, graphene paper, graphene mat, or graphene foam at the anode having the embedded main anode active material is connected to a first battery terminal tab to function as an anode current collector, There is no separate or additional anode current collector for supporting the film, graphene paper, graphene mat, or graphene foam. 6. The method of claim 5,
The graphene film, the graphene paper, the graphene mat, or the graphene foam at the cathode having the embedded main cathode active material is connected to the battery terminal tab to function as a cathode current collector, There is no separate or additional cathode current collector for supporting graphene paper, graphene mat, or graphene foam. 8. The method of claim 7,
The graphene film, the graphene paper, the graphene mat, or the graphene foam at the cathode having the embedded main cathode active material is connected to the second battery terminal tab, and the graphene film, There is no separate or additional cathode current collector for supporting paper, graphene mat, or graphene foam. The method according to claim 1,
Further comprising an anode current collector for supporting the anode or a cathode current collector for supporting the cathode. The method according to claim 1,
Wherein an amount of charge between Vi and Vf is 200 mAh / g or 400 mAh / cm < 3 > or more based on the weight or volume of the cathode active material. The method according to claim 1,
Wherein a cost amount between Vi and Vf is 400 mAh / g or 800 mAh / cm3 or more based on the weight or volume of the cathode active material. The method according to claim 1,
Wherein a cost amount between Vi and Vf is at least 1,000 mAh / g or at least 2,000 mAh / cm3 based on the weight or volume of the cathode active material. The method according to claim 1,
Wherein the main anode active material is Mg or Al,
The main cathode active material is sulfur (S) bonded to the graphene surface, a mixture of S and Se, or sulfur,
Wherein the electrolyte is selected from aqueous, organic, polymeric, or solid state electrolytes. The method according to claim 1,
Wherein the metal oxide, metal phosphate or metal sulfide is selected from tin oxide, cobalt oxide, nickel oxide, manganese oxide, vanadium oxide, iron phosphate, manganese phosphate, vanadium phosphate, transition metal sulfide, Electrochemical battery cell. An electrochemical battery cell comprising an anode having a primary anode active material, a cathode having a primary cathode active material, and an ion-conducting electrolyte in ionic contact with the anode and the cathode,
The initial output voltage Vi of the lower limit of 0.3 volts to the upper limit of 0.8 volts when the cell is measured at a 10% discharge depth (DoD), and the final output voltage Vf when measured at DoD of 90% And,
The voltage fluctuation ((Vi-Vf) / Vi) is ± 10% or less,
The amount of charge between Vi and Vf is 100 mAh / g or 200 mAh / cm3 or more based on the weight or volume of the cathode active material,
Wherein the main anode active material is selected from magnesium (Mg) or aluminum (Al), a mixture thereof, an alloy thereof, or a combination thereof,
Wherein the main cathode active material is selected from metal oxides, metal phosphates, metal sulfides, inorganic materials, or metals or semi-metals different from the main anode active material,
Wherein the metal or semimetal in the cathode is selected from the group consisting of Sn, Bi, Sb, In, Tell, P, Mg, Zinc, zinc, tin, manganese, iron, vanadium, cobalt, nickel, sulfur, selenium, An alloy thereof, or a combination thereof,
Wherein the electrolyte is selected from an aqueous, organic, polymeric, or solid state electrolyte that does not comprise an ionic electrolyte. 17. The method of claim 16,
Wherein the inorganic material is selected from carbon sulfur, a sulfur compound, a lithium polysulfide, a transition metal dichalcogenide, a transition metal trichalcogenide, or a combination thereof. The method according to claim 1,
Wherein the cathode further contains graphene as an electrochemical property modifier for the primary cathode active material,
Wherein the graphene increases cell capacitance or increases or decreases the cell output voltage. 17. The method of claim 16,
Wherein the cathode further contains graphene as an electrochemical property modifier for the primary cathode active material,
Wherein the graphene increases cell capacitance or increases or decreases the cell output voltage. 19. The method of claim 18,
Wherein the primary cathode active material is bonded to the surface of the graphene or physically supported by the surface of the graphene. 19. The method of claim 18,
Wherein said graphene comprises an initial graphene material having less than 0.01 weight percent non-carbon element, or a non-initial graphene material having between 0.01 weight percent and 50 weight percent non-carbon element,
Wherein said non-initial graphene is selected from the group consisting of graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrided graphene, boron- Pin, nitrogen-doped graphene, chemically functionalized graphene, or combinations thereof. The method according to claim 1,
An electrochemical battery cell in which the voltage fluctuation ((Vi-Vf) / Vi) is not more than +/- 5%. An electronic device comprising the electrochemical battery cell of claim 1 as a power source. 24. The method of claim 23,
A sensor, a driver, a wireless device, a wearable device, or a medical device electronically coupled to the electrochemical battery cell.

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